This changes the academy's previous guidance, which said children should ride in rear-facing seats until at least age 2. The new recommendation eliminates the age-specific milestone to turn a child's car seat around.

Car seat manufacturers are making seats that allow children to remain rear-facing until they reach 40 pounds, Dr. Benjamin Hoffman, lead author of the academy's updated guidelines, said in a statement.

"It's best to keep your child rear-facing as long as possible," Hoffman, chairman of the academy's Council on Injury, Violence and Poison, said in the statement. "This is still the safest way for children to ride."

By using the proper car seat, the risk of death or serious injury is lowered by more than 70%, according to the academy. All children younger than 13 years should be in a vehicle's back seat, it said.

Parents can find height and weight limits for a car seat in the instruction manual.

Once children reach the height or weight limit and shift to a forward-facing seat, they should use safety seats with harnesses for as long as possible, often up to 65 pounds, the pediatricians' group said. Once children exceed height or weight limits for those seats, they should use a belt-positioning booster seat until the lap and shoulder belts fit properly, often when the child has reached 4 feet 9 inches in height.